"Military units are on site; the number of victims and the causes of the crash have not yet been determined," said Colombian Defense Minister Pedro Sánchez, RCN reports.
The plane, a Hercules-type aircraft, crashed on takeoff - and the accident is said to have hit a rural area with farms nearby, according to RCN.
According to the Colombian military, at least 80 soldiers are feared to have been on board.
The governor of the Antioquia region, Andrés Julián Rendón, said that around 100 people were on board. The accident occurred near the Ecuadorian border, following an operation against drug-related activities.
